Pour alcohol into the foam, why does the foam disappear?

Foam is generated because the foaming agent reduces the gas-liquid interface tension and forms a strong surface on the foam surface. After the addition of alcohol, the alcohol adsorbs on the surface of the bubble and displaces the original foaming agent molecules, but the alcohol molecules cannot form a strong film, so the bubbles burst and the foam is destroyed.

Alcohol mainly oh has these properties:

1. Acidity and alkalinity

Ethanol. Not an acid (an acid in the general sense, it can not make an acid-base indicator.

discoloration, and does not have the universality of acids), the ethanol solution contains polarized oxygen-hydrogen bonds, which form alkoxy anion and protons (hydrogen ions) when ionized.

2. Reducibility

Ethanol is reducible and can be oxidized (catalyzed) to acetaldehyde.

It is even further oxidized to acetic acid. The culprit of alcoholism is usually thought to be acetaldehyde, which is somewhat toxic (ethanol can also be oxidized in the body, but more slowly because there is no catalyst), rather than alcohol that is drunk.

Ethanol is a good solvent that can dissolve many substances, so ethanol is commonly used to dissolve plant pigments or medicinal ingredients; Ethanol is also commonly used as a solvent for the reaction, so that the organic matter participating in the reaction is sumInorganicsAll can be dissolved, increase the contact area, and improveReaction rate

For example, in the saponification reaction of fats.

, the addition of ethanol dissolves both NaOH and oil, allowing them to be in full contact in a homogeneous (solution of the same solvent) and speeding up the reaction rate.

Due to the presence of hydrogen bonds, ethanol has strong deliquescent properties and can quickly absorb moisture from the air. The polarity of the hydroxyl group also makes many ionic compounds soluble in ethanol, such as sodium hydroxide.

potassium hydroxide, magnesium chloride, calcium chloride, ammonium chloride, ammonium bromide and sodium bromide, etc.; But sodium chloride.

and potassium chloride slightly soluble in ethanol.

Because the alcohol may have a chemical reaction to the foam, and then the bubbles will be eliminated.

Because alcohol may have a chemical reaction to the foam, the foam will disappear.

This is because the ingredients in the alcohol dissolve the foam and then the foam disappears.

This is a chemical reaction in which the alcohol is volatile and the bubbles are eliminated.

The alcohol volatilizes and causes the foam reaction to volatilize at the same time, so the foam will slowly disappear.

Because alcohol can corrode the foam and then dissolve the foam into nothing.

They may have some associated reactions, so the foam will disappear.

Because the alcohol will evaporate quickly when poured in, and then the bubbles will be eliminated.

It's a combination of hops and carbon dioxide!

When beer is poured into a cup, a lot of foam grows. This foam is called "hops". It's actually related to a gas called carbon dioxide.

In the beer production and brewing process, carbon dioxide is compressed, dissolved in the liquor, and then bottled and capped. When drinking beer, because the pressure inside the bottle is greater than that outside the bottle, as soon as the cap is opened, the carbon dioxide will be agitated outward, producing many bubbles; Pour the beer into the cup and the bubbles will bubble even more. Not only beer, but also carbon dioxide is pressed into water to make various summer drinks containing carbonated gas.

Why is there foam when pouring beer? After so many years, I can figure it out, look at it.

1. Deliquescence.

Due to the presence of hydrogen bonds, penitential ethanol has strong deliquescent properties and can quickly absorb moisture from the air. The moisture in the foam is absorbed, resulting in rapid elimination.

2. Solubility.

It can be miscible with water in any ratio; It is miscible in most organic solvents such as ether, chloroform, methanol, acetone, glycerol, etc. Alcohol dissolves both organic and inorganic substances participating in the reaction, increasing the contact area and increasing the reaction rate.

1. Ethanol is a good solvent, and the rock limb can dissolve many substances, so ethanol is commonly used to dissolve plant pigments or medicinal ingredients; Ethanol is also commonly used as the solvent for the reaction, so that the organic and inorganic substances participating in the reaction can dissolve the starvation, increase the contact area, and increase the reaction rate.

2. Ethanol is not an acid (an acid in a general sense, it cannot change the color of the acid-base indicator, nor does it have the general properties of acid), the ethanol solution contains polarized oxygen-hydrogen bonds, and when ionized, alkoxy anion ions and protons (hydrogen ions) are formed.

There is a certain amount of gas (mainly carbon dioxide) dissolved in the beer, and when we open the beer bottle, we hear it coming out.

The gas dissolved in the liquid will be released when the external pressure is low, and the gas molecules will easily combine when they meet other gas molecules, because even different gases, such as air and carbon dioxide, have many similarities in their properties, the so-called like aggregation. As a result, these molecules pull and pull at each other, and come together +1 4....Therefore, if there are foreign gas molecules in the beer, then the original carbon dioxide molecules in the beer will combine with these foreign molecules, accumulate into larger bubbles, and run out of the beer.

If there is a lot of foreign gases, the process will be very fast, and we can see a lot of bubbles coming out of the beer.

When stirring beer with chopsticks, on the one hand, some air will be absorbed on the rough chopsticks - that is, tiny bubbles; On the other hand, when stirring, air is brought into the beer, and even if it is water, air may be stirred in when stirred, and bubbles may be formed. At this point, the carbon dioxide quickly combines with the air and can't wait to run out, and we see the foam.

In the same way, beer served in glass will have less foam, while beer served in disposable paper cups will have the opposite. This is because glass is smoother than paper, there is much less air attached to it than coarse paper, and carbon dioxide does not accumulate easily.

Add a drop of soy sauce to the foam.

Stay for a while and disappear naturally.